Extensions of Exact and K-Mixing Dynamical Systems

Abstract We consider extensions of non-singular maps which are exact, respectively K-mixing, or at least have a decomposition into positive-measure components. The fibers the extension spaces countable (finite infinite) cardinality and action on them is assumed surjective bijective. call these systems, respectively, fiber-surjective fiber-bijective extensions. Technically, they skew products, though point view we take here not one generally associated with products. Our main results an Exact K-mixing Decomposition Theorem. latter can be used to show that large number periodic Lorentz gases (the term denoting general group Sinai billiards, including tubes slabs, in any dimension) K-mixing.